Biology Chapter 32 Exercise

Select the correct statement about the evolution of animals.

Identify the features that distinguish animals from organisms in other multicellular kingdoms.

Select the correct statement(s) about animal body plans.

What is the key difference between a coelom and a pseudocoelom?

Which feature of deuterostome development explains the formation of identical human twins?

Which of the following is a point of conflict between the phylogenetic analyses presented in these two figures?

The last common ancestor of all animals was probably a

Which statement is most consistent with the hypothesis that the Cambrian explosion was caused by the rise of predator-prey relationships?

Which of the following genetic processes may be most helpful in accounting for the Cambrian explosion?

Which of the following is radially symmetrical?

Gastrulation is the process that directly forms the _____.

Which of the following is NOT a characteristic of all animals?

An important trend in animal evolution was cephalization. An animal is said to show cephalization when it _____.

Which of the following animals does NOT have a body cavity?

During embryological development, the anus forms before the mouth in _____.

With the current molecular-based phylogeny in mind, rank the following from most inclusive to least inclusive. 1. ecdysozoan 2. protostome 3. eumetazoan 4. triploblastic

The most recently discovered phylum in the animal kingdom (1995) is the phylum Cycliophora. It includes three species of tiny organisms that live in large numbers on the outsides of the mouthparts and appendages of lobsters. The feeding stage permanently attaches to the lobster via an adhesive disk, and collects scraps of food from its host's feeding by capturing the scraps in a current created by a ring of cilia. The body is sac-like and has a U-shaped intestine that brings the anus close to the mouth. Cycliophorans are eucoelomate, do not molt (though their host does), and their embryos undergo spiral cleavage. Using similarities in embryonic development, body symmetry, and other anatomical features to assign an organism to a clade involves 1. cladistics based on body plan. 2. molecular-based phylogeny. 3. morphology-based phylogeny.